The objective of this research is to define the mechanism action of vitamin A at the molecular level in organs other than eye. Emphasis is given to investigation of possible alterations in the transcriptional mechanism during vitamin A deficiency. Efforts are made to characterize the properties and function of two newly discovered intracellular binding proteins for retinol (vitamin A) and retinoic acid. The levels of these binding proteins are examined during perinatal development of the rat.